ABSTRACT
【Objective】 To investigate the inhibitory effect of magnesium citrate （MgCit） on hyperphosphorus-induced VSMCs calcification and its mechanisms. 【Methods】 VSMCs were divided into the following groups： normal control group， high-phosphorus group， low-dose MgCit group， high-dose MgCit group and high-dose MgCit+NPS2143 （calcium-sensitive receptor inhibitor） group. Alizarin red staining was used for semi-quantitative analysis of VSMCs calcification and the calcium content in VSMCs was detected by the commercial kit. The osteogenic transdifferentiation parameters including alkaline phosphatase （ALP） activity， as well as mRNA and protein levels of smooth muscle 22α （SM22α）， runt-related transcription factor 2 （RUNX2） and bone morphogenetic protein 2 （BMP2）， were detected in each group. 【Results】 Compared with those in the control group， the calcium content of VSMCs in the model group was increased， ALP activity， and the mRNA and protein expressions of RUNX2 and BMP2 were increased， and the mRNA expression of SM22α was decreased （P<0.05）. MgCit could reduce VSMCs calcification， decrease ALP activity， decrease mRNA and protein levels of RUNX2 and BMP2， and increase mRNA levels of SM22α induced by high-phosphorous （P<0.05）. The above effects of MgCit were reduced when NPS2143 was administered simultaneously （P<0.05）. 【Conclusion】 MgCit can reduce VSMCs calcification and osteogenic transdifferentiation induced by high phosphorus through activating of CaSR.
ABSTRACT
Objective To investigate the inhibitory effects and mechanisms of diethyl citrate (Et2Cit) on oxidative stress and vascular calcification in chronic renal failure (CRF). Methods SD rats were divided into four groups: control group, model group, Et2Cit group and Et2Cit+NPS2143 (calcium sensitive receptor inhibitors) group. Alizarin red staining was used to detect aortic calcification in CRF rats. Concentrations of superoxide dismutase (SOD) and nitric oxide (NO) in the aorta and plasma of CRF rats were measured. The cells were divided into four groups: control group, high-phosphorus group, Et2Cit group, and Et2Cit+NPS2143 group. The levels of dihydroethidium (DHE) and reactive oxygen species (ROS) were detected by flow cytometry. Results Compared with that in the control group, the aortic calcification degree in the model group was significantly increased. Et2Cit intervention could reduce the aortic calcification level. Aorta and plasma SOD and NO contents in the model group were significantly decreased (P<0.05). Et2Cit intervention could increase SOD and NO contents in the aorta and plasma (P<0.05). However, when NPS2143 and Et2Cit were given simultaneously, the effect of Et2Cit in improving vascular calcification and oxidative stress levels were inhibited (P<0.05). DHE and ROS levels were increased in cells under high phosphorus environment (P<0.05), and Et2Cit intervention could decrease DHE and ROS levels (P<0.05). However, compared with Et2Cit group, DHE and ROS levels in Et2Cit+NPS2143 group were increased (P<0.05). Conclusion Et2Cit inhibited oxidative stress level in CRF vascular calcification, which is dependent on calcium-sensitive receptors.
ABSTRACT
OBJECTIVE@#This study aimed to investigate the effect of calcium ion (Ca²⁺) on the migration and osteogenic differentiation of human osteoblasts and explore the proper concentration and correlation mechanism.@*METHODS@#A series of Ca²⁺ solutions with different concentrations was prepared. Osteoblast migration was assessed by Transwell assay, and proliferation was studied via the CCK-8 colorimetric assay. The mRNA expression of osteogenic genes was examined via reverse transcription-polymerase chain reaction (RT-PCR), and the mineralized nodule was examined by alizarin red-S method. After calcium sensitive receptor (CaSR) antagonism, Ca²⁺-induced migration and osteogenic differentiation were analyzed.@*RESULTS@#In the migration experiment, 2, 4, and 6 mmol·L⁻¹ Ca²⁺ could promoted osteoblast migration at three timepoints (8, 16, and 24 h), whereas 10 mmol·L⁻¹ Ca²⁺ considerably inhibited migration at 8 h. The Ca²⁺ concentration range of 2-10 mmol·L⁻¹ could promote proliferation, osteogenic differentiation, and mineralization of human osteoblasts. Moreover, mineralization was predominantly induced by 8 and 10 mmol·L⁻¹ Ca²⁺. CaSR antagonism could reduce Ca²⁺-induced migration and osteogenic differentiation of human osteoblasts.@*CONCLUSIONS@#Low Ca²⁺ concentration favored osteoblast migration, whereas high Ca²⁺ concentration favored osteogenic differentiation. The Ca²⁺ concentrations of 4 and 6 mmol·L⁻¹ could substantially induce osteoblast migration and osteogenic differentiation, and the Ca²⁺-CaSR pathway participated in signal transduction.